1. Field of the Invention
The present invention relates to a countersink reamer for three dimensional interior/exterior small bores, and especially to a countersink reamer which can be easily locked on a conventional general electric (or pneumatic) hand tool for simple and fast abrasing rough edges in one way (or in both ways) on small bores drilled on a two-dimensional plane or a three-dimensional arciform surface on a normal workpiece, and especially for abrasing rough edges created on the three dimensional interior/exterior small bores when in drilling and by the way for countersink-reaming.
2. Description of the Prior Art
In a mechanical processing, generally, it is most convenient to use a drilling technique to get a straight bore with a small diameter in manufacturing.
Such shaped small bores made in a drilling processing technique, particularly those interior/exterior small bore rims on such bores, exceptionally tend to create rough edges; the rough edges on the bore rims will be the impediments of the assembling members to be fitted over or tapped, thereby, the accuracy of assembling can be adversely influenced; and therefore, the rough edges on the interior/exterior bore rims must be gotton rid of by grinding and cutting processes.
It has been known that, the way of getting rid of the rough edges on the interior/exterior bore rims mostly uses sand wheels or sponge wheels for grinding, and some may use a vibrational grinding process to eliminate the rough edges on the bore rims; however, sand wheels and sponge wheels for grinding can only be used to eliminate the rough edges on the exterior bore rims on a two-dimensional plane, they can not be placed in the areas allowing them to eliminate the rough edges on the interior walls of the bores, or on the interior bore rims on a two-dimensional plane or even on a three-dimensional arciform surface, these rough edges appear in a narrow and small bore, on a wall at a distal end or in a corner, or in an enclosed pipe hole, and neither the vibrational grinding processes using grinding media and grinding granules can eliminate the rough edges on the interior walls of the bores, or on the interior bore rims on a two-dimensional plane or on a three-dimensional arciform surface in these narrow environments. Therefore, non of the conventional techniques are suitable for synchronical grinding and countersink-reaming the rough edges on the interior/exterior bore rims, specially those rough edges on the three dimensional interior/exterior small bores drilled on the three dimensional arciform surfaces, these are the technical impediments ineliminable in the conventional techniques.